Electricity Bills of an Electrically Heated Detached House Reduced by 1 500 Euros Per Year


Antti Pesonen, who lives in the Helsinki Metropolitan Area, is happy with his decision; he had his house equipped with Themo Smart Thermostats in August 2021. Within a year, they have saved approximately 5 600 kWh of electricity by optimizing underfloor and ceiling heating in the house, shifting usage to the night-time. Compared to exchange electricity, his electricity bill has been reduced by as much as €1 500.


Interest in the Consumption of Electricity of a Detached House Sparked at the Right Time

The price of electricity and fuels began to rise sharply in the summer of 2021. Antti Pesonen wanted to find out where electricity was consumed in his house, which was built in the 1990s, and where savings could be achieved. He went over the electricity bills from previous years and measured the consumption of various devices. 

As the house has direct electric heating, the bulk of the electricity consumed by the property is understandably used on heating. The heating system comprises underfloor storage heating with ceiling heating in a couple of bedrooms. An air source heat pump is also used.

The next largest consumer of electricity is the boiler, followed by the electric sauna heater, as well as mechanical ventilation, freezer, and two refrigerators, which are always on. The remaining consumption of electricity, such as lighting, charging of mobile phones and computer use, and the wireless network has a limited impact. These are also areas where savings are harder to come by.


“The easiest and most effective way to start saving electricity was to optimize the consumption for heating. As the price of electricity has now risen to new heights, I can safely say I made the right move at the right time. After the installation of the Themo Smart Thermostats, the cost of electric heating has been reduced by 19 %.”


Themo is Now an Essential Element of a Smart Home

The 10 existing thermostats in Antti’s house in the bedrooms, bathroom, living room, kitchen, utility room, and the fireplace room were replaced with Themo Smart Thermostats. 8 of them are used to control underfloor heating and 2 control ceiling heating.

“I purchased Themo Smart Thermostats to reduce my consumption of electricity in order to both save money and conserve the environment. I reviewed the smart thermostats and services available on the market and chose Themo Smart Thermostats, because their use is not subject to a monthly fee, and I can control them myself. I am interested in the latest technologies and am in the process of converting our house into a smart home in various ways.”


Antti purchased the smart thermostats from Themo's online store. Antti called an electrician to install the devices and configured the room-specific temperature settings personally using the Themo app. The installation was slightly complicated by the fact that some parts of the existing underfloor heating system were not directly compatible with Themo’s thermal cable. The installation issues and other questions were however quickly resolved with the timely and proficient support offered by Themo.

Savings of Approximately €1 500 Compared to Exchange Electricity

Antti has been monitoring and calculating the consumption of electricity in his house quite closely. Taking into account the variation in outdoor temperatures, the consumption of electricity has been reduced by 19% within the year following the installation of the Themo Smart Thermostats and the most significant savings have been achieved during the colder winter months. The savings have amounted to 127 euros per month on average.


“When I add up the price of the Themo Smart Thermostats and the installation work, the investment has paid for itself within a year in a detached house of this size and at the electricity rates of the past year. And if the price of electricity continues to rise, the savings will increase even further. I intend to install Themo Smart Thermostats at our holiday home as well.”


The electricity market is strongly headed toward exchange electricity, and the availability of fixed-price electricity contracts is quite limited. “Most existing electricity contracts will expire within 6–12 months on average, and a significant increase in the price of electricity could be expected at that time. Reducing the consumption of electricity should become relevant to most people at that point at the latest,” Antti says.


Electricity consumption before (black bars) and after (purple charts) installing Themo Smart Thermostats.The vertical line indicates the influence of the outside temperature on the heating demand in an electrically heated detached house.


Suitable and Sufficient Temperature in Each Room

By controlling the Themo smart thermostats, Antti was able to lower the indoor temperature in the house by 2–4 degrees depending on the room and time of day. The initial temperature was +24 °C, whereas the temperature inside the house is now +22 °C where appropriate. As this is not sufficient for the bathroom, the temperature in there is raised a few degrees higher in the mornings and evenings.

Read how Antti compared the consumption of electricity and what he thinks about Themo's advantages in terms of the optimization of electricity transmission.

Is your house equipped with underfloor heating? Purchase a Themo Smart Thermostat from our online store and begin saving electricity and conserving the environment!

Purchase here

References and articles

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